The present invention relates to a safety device for protection of a passenger occupying a motor vehicle seat.
The invention relates more particularly to a safety device of the type comprising, in combination, a seat belt and an inflatable airbag for the possibility of frontal collision, which device is intended as equipment for a motor vehicle seat.
The association of an inflatable airbag with a seat belt has already been proposed for example in patents such as U.S. Pat. No. 5,062,662 or U.S. Pat. No. 5,597,178.
In these two patents the inflatable airbag is supported by the webbing of the seat belt, and it can be associated either with the lap loop thereof or with the diagonal or shoulder loop, in the case of a belt with three-point fixation.
Such a design makes it possible to improve protection of the passengers in the event of collision, but it does not take into account the fact that the seats are often occupied by children.
In particular, all the supplementary systems for restraining and holding children are currently held by the seat belt or, in the future, will be fixed to fixation points defined by xe2x80x9cISOFIXxe2x80x9d, an international standard.
The possible presence of an inflatable airbag with frontal effect makes it potentially dangerous for a child to occupy a seat, and in such a case it is absolutely necessary to provide a possibility for disabling the means for inflation of the inflatable airbag during use of systems for restraining and holding children and/or during occupation of seats by children.
A first solution comprises providing means for detecting the weight and/or height of seat occupants, but such means are complex in design, costly and not completely reliable.
In the case of vehicles equipped with fixation points according to the xe2x80x9cISOFIXxe2x80x9d standard, disabling means can be associated with the fixations, but they do not resolve the problems mentioned in the foregoing for modern vehicles in which the child-restraining means are held by the seat belt.
In order to remedy these drawbacks, the invention proposes a safety device for protection of a passenger occupying a motor vehicle seat, which device is of the type comprising:
a seat belt with webbing whose two ends can be anchored to the vehicle structure and an intermediate part of which can occupy either a storage position or a use position, in which it extends along part of the passenger""s body; and
an inflatable airbag to restrain the passenger in the event of collision, which airbag is carried by a support which can be moved between a storage position and a use position, in which the support and the deflated airbag extend along part of the passenger""s body; characterized in that the support of the inflatable airbag is a flexible strap independent of the webbing of the seat belt and an intermediate part of which, when the inflatable airbag is in use position, extends along part of the passenger""s body.
According to other characteristics of the invention:
the means for inflating the airbag are disabled when the airbag is not in use position;
the support strap of the inflatable airbag is associated with means for detachable fixation thereof in use position, which means control the disabling of the inflation means;
the means for detachable fixation of the support strap of the inflatable airbag comprise a latch which is carried by the support strap and which, when the airbag is in use position, is received releasably in a catch;
the catch is fixed to the webbing of the seat belt;
the catch is fixed to the vehicle structure;
the seat belt is provided with a latch for fastening the seat belt in use position, the body of which latch is attached to the webbing and which is designed to be received releasably in a catch fixed to the vehicle structure, and the catch associated with the latch for fixation of the support strap of the inflatable airbag is associated with the body of the latch for fastening the seat belt;
when the inflatable airbag is in storage position, the fixation latch carried by the support strap is received in a catch fixed to the structure of the vehicle or seat;
when the inflatable airbag is in use position, the support strap of the inflatable airbag extends parallel to the lap loop of the webbing of the seat belt;
one of the anchor points of one of the free ends of the webbing of the seat belt is associated with a device for tensioning the webbing with a force which is adjustable at least between an upper value when the seat belt is used without the inflatable airbag and a lower value when the seat belt is used in combination with the inflatable airbag, the adjustment of the said value being automatically achieved according to whether the means for inflation of the inflatable airbag are in disabled or activated state.